Chris's Corner - Happy Easter!

This will play 

NE MO and many areas in Iowa got clobbered today!

Im confused? I dont see a message.

We were never under level 3 here. Just 2. And that is not hype. That's a forecast by the spc. Hype is when it's all over the place being talked about by everyone. IMO

It is a "Windy-Wednesday" in St. Louis! Gusts so far have been bumping up into the high 30 mph range in spots. That may decrease a little for a while and then ramp up again somewhat this afternoon. Either way... it's a windy day with bursts of higher gusts at times. There will be a somewhat elevated wildfire risk today as a result of the winds and dry air sweeping across the region.

The next system of interest is a strong cold front that will cross the area tomorrow. Originally, the threat for severe storms with this front looked to be focused well to our south... but some of the latest trends have nudged that back north a bit. I think the SPC Level 2 outlook for tomorrow has come a bit too far north... I do think areas along and south of I-70 will have the greatest risk for severe weather tomorrow... from late morning through early evening.

The Thursday Breakdown....
There could be two rounds of storms with this system. The first will come with a complex of thunderstorms that is expected to develop late tonight over northwest Missouri and track southeast reaching metro STL around noon or shortly thereafter. This round of storms will be capable of strong wind gusts over central Missouri but should weaken as it approaches the metro. As this first round clears the area a second round of storms will try and develop over central Missouri... and follow along behind the first round... only slightly further to the south. This round will initially be capapble of very large hail, damaging winds and possibly tornadoes. The risk zone with this second round of storms during the afternoon and early evening will be south of I-70... so over the southern 1/3d to 1/2 of the viewing (which goes down into Reynolds and Iron Counties). Between the two, our region will be under the risk of some sort of severe weather from late in the morning through early evening... roughly 10am to 8pm.

The details for tomorrow are very much a work in progress and will be greatly influenced by how long the first round of storms survives. I could see a scenario where that midday round of storms is THE round of storms and supresses everything else back into far southern Missouri...which is where I expected it to be based on previous guidance. That is the best case scenario for most of our viewing area of course.

They don't even issue level 3 outlooks until the day 3 outlooks are put out. That would have been Sunday. The metro area was always in a 2. We were in a risk area as of late last week for day 4 and for day 5.

No way. Too high.
Too high? What does that mean, too high?
Too high, I thought.
At first I thought it was too high.
Who gives a sh**. It's gone.

By the way, Chris posed the question a few days ago about whether the SPC probabilities were helpful or confusing to the general public. And I agree that those probability numbers are likely confusing for the general public and I would add to that that the VAST majority of people have no idea at all what those values actually represent. To make matters worse a mere 13% in those tornado probabilities can be the difference between barely any risk and particularly dangerous situation. I do think the risk categories are helpful though...well...expect maybe the category names could use some tweaking (particularly Enhanced vs. Moderate).

I am interested in what the intent the SPC has for those categories. I think what happened yesterday led some people to believe that it was “overhyped.” The people that mentioned that, I said, “the heavy stuff was always supposed to be to the north and north west of St. Louis.” I think when people see a category of 2, they assume severe weather is going to be probable. I think the general public is very unaware of what the difference between the categories is, and what they are supposed to do with that information.

Futurecast teeing up the ol STL Split for tomorrow I see...

My 2 cents....radio DJs tend to hype but that might not be bad. It tells ppl to get tuned to their fave met.

I do think the translation to a category number is too weatherchannelesque. As if i had any say, id tell them to just tell it like it is, and dont be all weatherchannelish. If presenting without graphics, dont get fancy. Mention the chance for severe thunderstorms. With graphics to the general public (ie tv to mass audiences) the story should tell more details. It might be ok to use a standard decision to say things like "elevated risk" of a certain peril (eg elevated risk of damaging hail). In high confidence of high risk situations, i believe enhanced verbiage is the way to go.

If presenting with or without graphics to weather hobbyists, i like the percents, even if they dont verify bc they give me insight into what the pros are thinking. The trouble with that though, is, well i'll just say word gets out to the wrong ppl who want to sensationalize.

I dont think the recent event was hyped by credible sources, but my sources are few. The value of this blog is high to me bc it gives me that insight. Private meteorologists who offer paid services such as Beau Dodson to our southeast would also benefit well with a tiered presentation of weather.

For me, the biggest question is how far will overnight MCS progress to the east and southeast and what impact does that have on the effective boundary.
A couple of themes we see repeated frequently with these types of events...
1) Models are very often too slow moving the line of storms east and south
2) Models weaken the initial MCS too quickly and underestimate the southeast penetration of the effective boundary
3) Models... especially the NAM/NAM3k are way too generous with the low level moisture and fail to capture mixing that drops surface dew points. The HRRR is strongly hinting at this... although it too has a history of drying out the low levels too quickly at times.

So... I'm going to work on the idea that the early MCS will be faster moving and end up further south... but I don't want to get too aggressive with that considering the overwhelming support for slower/conservative overnight MCS motion. I'm also going to knock down the NAM dew points a little bit. The end result is a focus zone for severe storms that is roughly along and south of I-70 with a main focus on southeast Missouri into Southern Illinois. Metro STL is included in that region of concern... although it is on the far northwestern edge.

I'm thinking widespread wind damage with gusts of 60-80 mph possible...in addition to a few small, fast hitting tornadoes and a few pockets of large hail. The wind potential is actually highlighted in the drier skew T's with an inverted V signature in some of the model data. Those larger dew point depressions below the cloud level will encourage evaporational cooling and parcel acceleration as rain falls into the lower Td air mass. Greater low level moisture will increase the tornado potential by increasing SBCAPE.

Timing... our northwest counties may see storms as early as 10am-noon....whatever is left of the overnight MCS.
That boundary will either generate new storms... or re-intensify as it moves south and east early in the afternoon. Either way, an intensifying broken line of storms or LEWPS will march quickly southeast across eastern Missouri and southern Illinois sometime between 2pm and 6pm.

Stormy looking skies this morning. I'm definitely concerned about wind damage/power outages tonight with that second batch that the models want to develop after the first one goes through the metro.

Reed thinks we are in the Zone 🌪️